1. Field of the Invention
The present invention relates to an image recording apparatus such as a copying machine or a printer in which a photosensitive recording medium is employed, and more particularly to such an image forming apparatus that employs a continuous form photosensitive recording medium.
2. Discussion of the Related Art
Generally, an image recording apparatus which uses a photosensitive recording medium employs, for example, as disclosed in U.S. Pat. No. 4,903,070, the disclosure of which is herein incorporated by reference, an elongated web-like microcapsule sheet coated with a plurality of photo and pressure sensitive microcapsules, each microcapsule enveloping therein a chromogenic material and a photosensitive resin, and a developer sheet coated with developing material which produces an output image upon reaction with a chromogenic material, as is well known in the art.
The image recording apparatus comprises means for receiving the elongated web-like microcapsule sheet wound around a cartridge shaft and retained in a cartridge, an exposing unit for exposing the microcapsule sheet disposed at an exposure table to form a latent image thereon, a developer sheet feeding unit for feeding a developer sheet from a developer sheet cassette which stores therein, for example, a stack of developer sheets toward an exposed microcapsule sheet, a pressure developing unit for pressurizing the exposed microcapsule sheet superposed with the developer sheet to thereby form an output image on the developer sheet, a separating unit for separating the exposed microcapsule sheet from the developer sheet, a taking-up unit for taking-up the separated microcapsule sheet, and a thermal fixing unit for fixing the output image on the developer sheet.
In this type of image recording apparatus, the elongated microcapsule sheet drawn out of the cartridge passes through the exposing unit, the pressure developing unit and the separating unit, and is taken up by a taking-up unit. The developer sheet and superposed elongated microcapsule sheet containing a latent image are pressurized by the pressure developing unit, and are separated from each other by the separating unit and then the developer sheet is subjected to thermal fixing in the thermal fixing unit. At this time, the copying operation is completed.
However, upon completion of the above copying operation, the leading edge of the unexposed portion of the microcapsule sheet has passed through the pressure developing unit. If the next copying operation is immediately performed in the above mentioned situation, an unexposed portion of microcapsule sheet provided between the trailing edge of the exposed area from the preceding copying operation (now located adjacent the separating unit) and the leading edge of the next exposing area for the next copying operation (now located near the exposing unit), was not fully utilized, resulting in waste of the microcapsule sheet.
In order to prevent waste of photo-pressure sensitive recording sheet, U.S. Pat. No. 4,801,976, the disclosure of which is herein incorporated by reference, discloses a copying machine for copying an image on a photo-pressure sensitive recording sheet. The copying machine comprises an exposing unit for exposing the photo-pressure sensitive sheet placed at an exposure position to form a latent image thereon, a magnification detection unit for detecting the degree of magnification of the image exposed by the exposing unit, and an exposure area controlling unit for controlling a feeding unit in response to said detection unit, whereby the photo-pressure sensitive sheet is exposed by the exposing unit from a leading edge thereof.
However, in this type of conventional copying machine, the leading edge of the photo-pressure sensitive recording sheet is not controlled to be located at the proper exposure position until after the photo-pressure sensitive recording medium having a desired image has been discharged out of the copying machine. For the above mentioned reason, a user must wait for a time period during the adjustment of the leading edge of the photo-pressure sensitive recording sheet to the proper exposure position before proceeding with the next copying operation, after the end of the preceding copying operation. If the user did not wait for this adjustment to occur, but instead proceeded with the next copying operation, a portion of the photosensitive recording medium was wasted.
When the mode where a plurality of images are copied sequentially in one continuous operation is set in these types of image recording machines, a large quantity of the photosensitive recording medium is wasted because the above-described adjusting operation is not performed between each of the multiple consecutive copies. For example, it is often desirable to operate these types of image recording devices in a plural image recording mode wherein a user actuates a plural copy set key a single time to cause a copying operation (including exposing, developing, separating, etc.) to occur more than one time. Typically the plural image recording mode is used when more than one copy of an image is desired. Additionally, the plural image mode can be used if a document handler is employed with the image recording device to consecutively place a sequence of images to be copied on a support stand glass of the image recording device. In this case, the image recording device would perform a copying operation as each image to be copied is placed on the support stand glass. Since the photosensitive recording medium is continuously fed by the image recording device when in this plural image recording mode, even during the time between exposure operations of consecutive copying operations, a portion of the photosensitive recording medium will not be exposed with an image and thus will be wasted.